Identity: Light and Misa are responsible for the deaths of people; Light and Misa are the Kiras, killing everyone who gets in their way. After all, everyone who stood in their way died.
Goal: Light became consumed by his own ambition and ideals. After obtaining the Death Note, Light killed all criminals. Light's motive is to create a perfect world free of evil and to be the god of that new world. After all, the world is a rotten apple.